Preparation of catalyst for the hydrogenation of oils



\ Patented Jan. 15, 1935 PATENT OFFICE PREPARATION or CATALYST FOR; THEnrnnocnms'rron F orLs I Owen G. Bennett and Joseph 0. W.

Frazer, Baltimore, MIL; said Bennett assignor to Catalyst ResearchCorporation, poration of Maryland Baltimore, Ma, a cor-' f 1 g No.Drawing. Application ltgarch -1o, 1931,

. SerialNo. 523,l

4 Claims. (C1. za-zse) This .invention relates to the hydrogenation ofoils, and it is among itsobjects to provide catalysis for thehydrogenation ,Of oils which are readily prepared in a state ofJhighactivity, are 5 free, or substantially free, from oxide and otheractivity-reducing impurities, possess great hydrogen adsorptivepower,'-are eflicient and of long life.

,The invention is predicated upon our discovery that particularlysatisfactory hydrogenation catalysts may be obtained by alloying oramalgamatirig nickel with mercury, removing the mercury from the alloyby vacuum distillation, and protecting the residual finely divided andhighly'ac- 1 tive nickel from oxygen-containing gases and similaractivity-reducing agents. I

In the practice of the invention alloy.containin: nickel is firstprepared as by amalgamating metallic nickel with mercury. Mercury doesnot readily wet and amalgamate with nickel, but this maybe effectedquickly and easily if hydrogen is first deposited, electrolytically uponthe nickel. For instance, an electric current is passed through asolution of sulfuric acid, sodium carbonate or 2 the like, the nickel tobe amalgamated acting as cathode. As thus' treated the nickel may beamalgamated readily with mercury or. solutions of mercury salts.

In the preferred practice of the invention the 0 nickel amalgams areprepared directly by electrodeposition. In this embodiment a nickelsaltsolution is electrolyzed in a cell having a mercury cathode, the currentand voltage being regulated to eflect depositionof nickel. The moreconcen- 35 trated the amalgams, the higher are theyields.

However, for ease of handling it is preferable to use relatively liquidamalgams.

When an alloy containing the desired amount of nickel has been preparedit is transferred with- 40 out undue exposure to air, toany suitabledistillation apparatus and the mercury is distilled from it undervacuum. The most satisfactory results are obtained by the use of veryhighvac- 'uum for this results in lowering of the distilla- 45 tiontemperature, which is favorable to the production of the most activematerial. The distillation container should have ample vapor space,because the amalgam usually swells considerably during the first stagesof the distillation process.

50 Normally a container having twice the cubic capacity of the amalgambeing distilled will suffice.

When the mercury has been entirely removed,

' the nickel remains in the form of finely-divided 65 particles ofmetallic nickel which are highly active and whose surfaces are freemetal, i. e., free from oxide. These characteristics of the nickelprepared by our process appear in various ways. For example, nickelordinarily can not be wet directly by mercury. But thenickel produced by5 our process is immediately wet when contacted with mercury. This isindicative of the freedom of our product from oxide, and it shows thatthe surfaces of the particles consist chiefly, if not wholly, of freemetal. The activity of our cata- 10' lytic nickel is further manifestedby the fact that it adsorbs five tosix times more hydrogen than nickelprepared by the customary oxide reduction methods.

Furthermore, nickel prepared in this manner oxidizes rapidly whenexposed to oxygen, and our 1 tests have shown that it should beprotected from oxygen-containing gases and other activity-reducingagents in order to preserve'it in a state of maximum activity. This maybe done by sealing the nickel in the container when distillation iscomplete. The container may then be openedunder the 'oil to behydrogenated. Preferably,

however, our catalysts are protected by transferring them to anactivity-protective fluid. For instance, the nickel may be transferred,without exposure to the atmosphere, to the oil which is to behydrogenated. For most purposes. and for ease of adding definiteconcentrations of catalyst,

a known weight of oil, suillcient to cover and protect the nickel, isused. After the nickel has been covered by the oil, the mixture is againweighed. Definite. weights of the mixture may then be taken to addto-the body of oil to" be hydrogenated. Or, if preferred, it may beplaced in a container filled with carbon dioxide gas.

Our catalysts may be substituted for those now used in any of thecommercial hydrogenations procedures. Their eflicacy is shown by testswhich we have made. In one test 2.5 grams of nickel, prepared asdescribed above, were suspended in 500 grams of cotton seed oil havingan iodine number of 108.5 by the Wijs method. This mixture'was thentreated during three hours at a temperature of 180 C with hydrogen under125 pounds pressure, whilc stirring continuously with a propeller tankstirrer rotated at 860 R. P. M.

The hydrogenation efliciency of our catalyst is shown by the fact thatafter this treatment the iodine number was-reduced to 44.

Other things being equal, the rate and degree of hydrogenation aredependent upon the concentration of nickel used. In a further test theamount of catalyst waszdoubled, the other conditions remaining the same.The hydrogenated product of this test showed an iodine number of 19.7.

The hydrogenated products obtained in all of our tests were ofsatisfactory quality, being pure white, of pleasant odor and good taste.The hardness may be varied from a grease-like consistency to very hardproducts resembling waxes, depending upon the extent of hydrogenation.The nickel prepared by the process provided by this invention isexceedingly finely divided, which is desirable, as it aids themaintenance in suspen:- sion in the oil. However, it settles readilywhen agitation ceases.

A further advantage of our nickel catalysts resides in the ease withwhich they may be revivified when their activity finally decreases inuse, or if they become inadvertently oxidized. After being freed fromoil the catalyst is reamalgamated and processed as described above. Boththis procedure, and that of initial preparation, are simpler and lesstedious than those previously available. Furthermore, by observing thesimple precautions noted hereinabovecatalysts of high activity areconsistently obtained. That is not always so with the processes knownpreviously.

The claims presented herein are drawn to nickel hydrogenation catalystsand method of preparing them. Claims directed to the preparation ofsupported metallic catalysts through the amalgamation method disclosedherein are embodied in our copending application Serial No. 523,175,filed concurrently herewith.

According to the provisions of the patent statutes, we have explainedthe principle of our invention and have described-what we now considerto represent its best embodiment. However, we desire to have itunderstood that, within the scope of the appended claims, the inventionmay The settled sludge may be used, to hydrogenate further batches.

be practiced otherwise than as specifically described.

We claim:

1. In a process of preparing a metallic catalyst for the hydrogenationof oils, the steps comprising vacuum distilling a nickel-mercury amalgamto remove the mercury therefrom and thereby forming metallic nickel in afinely divided form which is readily suspendible in oil and highlycatalytically active in the hydrogenation of oil.

2. In a process of preparing ametallic catalyst for the hydrogenationofoils, the step comprising vacuum distilling a nickel-mercury amalgam toremove the mercury therefrom and thereby forming metallic nickel in afinely divided form which is readily suspendible in oil and highlycatalytically active in the hydrogenation of oil.

3. A process of preparing a metallic catalyst for the hydrogenation ofoils, comprising removing the mercury from a nickel-mercury amalgam byvacuum distillation and thereby forming metallic nickel in a highlycatalytically active finely divided form which is readily suspendible inoil, and without unduly exposing the highly active finely dividedmetallic nickel residue thus obtained to oxygen-containing gasestransferring it to an activity-protecting fluid.

4. A process of preparing a metallic catalyst for the hydrogenation ofoils, comprising removing the mercury from a nickel-mercury amalgam byvacuum distillation and thereby forming metallic nickel in a highlycatalytically active and finely divided form readily suspendible in oil,and mixing the highly active finely divided metallic nickel residue thusobtained with an oil without exposing it to oxygen-containing gases.

- OWEN G. BENNETT. JOSEPH C. W. FRAZER.

